BAGHDAD • Iraqi forces have tightened the noose around Islamic State in Iraq and Syria (ISIS) extremists making their last stand in the western city of Ramadi, officials said yesterday.

Iraqi forces have encircled the government complex in Ramadi, ISIS' last stronghold in the western city, and are about to enter it, joint operations command spokesman Yahya Rasool told Reuters. "We're clearing the buildings and streets around the complex of bombs in preparation to go in," he said.

Recapturing Ramadi, which fell to the militants in May, would be one of the most significant victories for Iraq's armed forces since ISIS swept across a third of the country last year.

Ramadi lies about 100km west of Baghdad and is the capital of Anbar, which is Iraq's largest province and shares borders with Syria, Jordan and Saudi Arabia.

The militants "seem to have fled the complex, we're not encountering any resistance", said Mr Sabah al-Numani, a spokesman for the counter-terrorism units that are leading the fight on the government side. "We're seeing lots of (ISIS) bodies, killed in the air strikes on the compound," he told Reuters.

The Iraqi government forces are backed by air support from a global coalition led by the United States. But hundreds of booby traps and roadside bombs combined with sniper fire and suicide car bomb attacks meant that, six days into their big push, they had some fighting to do to retake the city.

Estimates at the beginning of the operation were that no more than 400 ISIS fighters remained hunkered down in central Ramadi and dozens have since been killed.

Iraqi military sources say that more than 50 militants were killed in the past 48 hours alone.

Shi'ite militias backed by Iran, which have played a major role in other offensives against ISIS, have been kept away by the Iraqi government from the battlefield in Ramadi to avoid sectarian tensions.

If the offensive in Ramadi succeeds, it will be the second main city to be retaken from ISIS after Tikrit, in April. Officials said it would be handed over to the local police and to a Sunni tribal force.

After Ramadi, the army plans to move to retake the northern city of Mosul, the biggest population centre under ISIS in Iraq and Syria.

Dislodging the militants from Mosul, which had a pre-war population close to two million, would effectively abolish their state structure in Iraq and deprive them of a major source of funding, which comes partly from oil and partly from fees and taxes on residents.

An impediment to the Iraqi forces' advance in Ramadi has been the presence of pockets of civilians in combat zones, many of them used as human shields by ISIS. Civilians who escaped said that after being taken by the army to camps east of Ramadi, there was little food for those left behind.

One of them said he and his family were rescued after retreating ISIS fighters used them as human shields to leave the city.

REUTERS, AGENCE FRANCE-PRESSE